1. Field of the Invention:
This invention relates to an endoscope apparatus provided with an endoscope having a driving means for bending a bendable part with a motor.
2. Related Art Statement
There is already extensively used an endoscope (scope or fiber scrope) whereby, by inserting an elongate insertable part into a body cavity, organs within the body cavity can be diagnosed or inspected. It is used for not only medical but also industrial uses in observing or inspecting objects within a pipe of a boiler, machine or chemical plant or within a machine.
Further, there are used various endoscopes using such solid state imaging device as a charge coupled device (CCD) for the imaging means.
There is recently suggested an endoscope wherein a motor is used for a driving means for a bending operation of bending, for example, vertically/horizontally a bendable part provided in an insertable part of the above mentioned endoscope.
However, if the operation of bending the insertable part is thus electrically made, in the case of the bending operation, the bent state of the insertable part and the size of the load then will not be easily felt by hand. Therefore, there has been a problem that the insertable part will be bent more than is required within the body cavity and will contact at the tip with the body cavity wall or the like so strongly as to hurt it in the worst case.
An endoscope apparatus provided with a means for solving the above described problem is suggested, for example, in the publication of Japanese patent application laid open No. 87530/1986.
However, in the above described endoscope apparatus, in case the insertable part strongly contacts at the tip with the body cavity wall or the like, the bending will only stop but the problem that the danger of hurting the body cavity wall or the like will not be able to be avoided will still remain.
Also, in the case of inserting the insertable part, for example, of a medical endoscope through, for example, a spleen bent part of a large bending angle in the large intestine, if the insertable part is only pushed in, the insertable part on the tip side will only push the body cavity wall in the spleen bent part, it will be difficult to insert the insertable part and further the insertable part on the tip side will be Pushed back by the body cavity wall in some case.
In order to advance the insertable part in the above described state, it is necessary to make the bending angle of the bendable part substantially straighrt and at the same time to make an operation of pushing in the insertable part and there is a problem that the operation requires a skill.
As a means of solving such problems, for example, the pesent applicant suggests to make the bending angle of the bendable part substantially straight by using an elastic sheath for the bendable part to utilize the elasticity of this sheath as shown in the publication of Japanese patent application laid open No. 252128/1988.
However, in the endoscope using a motor for the driving means for bending the bendable part, in case the lever of a bending switch is placed in a neutral position, the bendable part will act to be fixed as bent in a predetermined direction, therefore there will be problems that, in order to make the bending angle a predetermined angle, for example, substantially straight, the lever will have to be operated to bend the bendable part in the direction reverse to the bending direction and that the direction will be missed during the operation and the operation will be complicated.
Further, in such endoscope having a motor as is described above, in case a momentary switch is used for the above mentioned bending switch, the operator will not be able to easily recognize the bending angle of the above mentioned bendable part and, even if a bending angle displaying means for displaying the bending angle is provided, the bending direction, for example, for making the bendable part substantially straight will have to be judged at a moment from the bending angle displayed by the bending angle displaying means and there is a problem that a skill is required.